The present disclosure relates to inspection tools, and more particularly, to precision inspection tools for performing quality control inspections on gas turbine engine fan blades.
During the manufacturing of a gas turbine engine, individual fan blades are processed prior to their assembly into a fan assembly. Fan blades can be made of aluminum or an aluminum alloy, to which a chemical coating material is applied to minimize erosion and wear during operation of the gas turbine engine. As exemplary processing process applies a masking material to various regions on a fan blade to define the boundary of the subsequent coating material. The root region and platform edge are exemplary regions that can be masked and coated. Masking material can be applied by hand and then inspected to assure the boundaries of the masking material meets dimensional requirements. The chemical coating material is then applied, the masking material is removed, and the coating is inspected to assure the boundaries of the coating material meets dimensional requirements. In exemplary inspection processes involving the root and platform regions of a fan blade, metallic hand-held calipers are used to measure the distance from the root end to the root masking or coating edge, and from the platform edge to the platform masking or coating edge. Because the platform edge can span the length of the fan blade, multiple platform measurement locations are usually required. The inspector generally evaluates if each measurement lies within the tolerance band for the particular masking region, and if not, corrective action may be required to be taken. Because the masking material is soft it can be susceptible to damage during the inspection process, and damaged masking material can require corrective action. Similarly, the coating material is subject to damage during the inspection process, and damaged coating material can require corrective action. Metallic hand-held calipers can scratch the masking and/or coating material, which can require rework. Accordingly, the masking and coating inspection processes can be time-consuming.